Tour Magazine Aero Frame Test (wind tunnel) - Anyone read it

Discuss light weight issues concerning road bikes & parts.
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kbbpll
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by kbbpll


VNTech
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by VNTech

djconnel wrote:
Waldo wrote:Our stated likely ranges of yaw are based on years of actually collecting on-bike data at a range of velocities (I'm certainly not averaging 40 kph on my typical rides) and in a range of conditions, locales, etc. This led us to the bi-modal curve we now use that suggests the bulk of effective yaw angles for most cyclists will be on 10-15 degrees.


Most of the time I'm tooling around at 25 kph. I care about wind resistance on aero-optimized equipment at crunch time in races on flat roads. I don't care during "average typical" conditions, nor for that matter when the pack is cruising along in a race. So my estimate is clearly for when it actually matters.


I was going to ask about this. Would it not make more sense, as a racing product, to optimize the shape for those moments when aerodynamics is most important to a race result? Off the front, alone or in a small group, at 40-45kph?

Otherwise, it seems they would be optimized for everyday riders rather than racers, and I can't imagine you guys would have made a decision like that.
VeloNews Magazine/VeloNews.com tech

airwise
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by airwise

Have any of you guys actually won a race on an aero bike?

Just wondering as I've never seen one cross the line first in an amateur road race and I get to see a lot of those.

Given that the rolling resistance of a tyre can vary more than the power gains of these framesets I do honestly wonder why these garner so much attention here when they are both non weight weenie and less enjoyable to ride.

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Waldo
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by Waldo

There is a patent on the hybrid toroidal rim, and there is an application for the Firecrest shape. I've only had cursory dealings on the patent side of things but it's certainly interesting to see what constitutes a patent that's easily enforced, claims that are easily dismissed, things like that.

The fun thing with all the Firecrestish rim profiles out there now is that it's like what we've seen with previous rim profiles-a half millimeter here or there can make a massive difference in drag values. The difference is now we're able to see that it also makes a significant difference in vortex shedding frequency off the wheel as well as steering torque, both of which are a significant part of wheel stability. We've also provided volumes of data on this subject, some of which has been presented at the AIAA conferences over the past few years (that work was not done by us but rather the PhD at our CFD post-processor). Other data seems curiously absent, but since other companies have clever acronyms describing how they've enhanced the stability of their wheels, I'm sure they're all over it.

Dan, I think we'll have to agree to disagree here. The data I've got is not easily presented here and doesn't seem like it's going to be sufficient to overcome your assumption-based estimates so we'll leave it at that.

Caley, the point I was trying to make is that we've got data sets applicable to a variety of conditions. Lots of good data for Pro Tour-level TTs, age-grouper triathlon events, and racing at a variety of speeds and in some smaller groups. The comment about me not averaging 40 km/hr was to illustrate that we also are considering the lower end of the velocity range for racing.

So, given all that data, it must be truly difficult to "optimize" (I think we all need to use that word less, myself included) for all these different scenarios, right? Well, conveniently enough there's a fair amount of convergence in the data (gross abbreviation of analysis follows-need to get on my ride to work to see what we'll find in today's wind). Even in the case of a relatively low wind velocity (10 km/hr), your maximum effective yaw angle ranges from 21.8 degrees at 25 km/hr to 14.0 degrees at 40 km/hr. If you increase wind velocity to 15 km/hr that 14.0 degrees at 40 km/hr becomes 20.6; of course in all cases the bulk of effective yaw angles will be below this value.

It's a long and boring process describing how we arrived at our final analysis (that quote about lies, damn lies, and statistics seems appropriate), but we're confident that we're incorporating the bulk of racing conditions with our stated range of targeted yaw angles.

I think we've derailed this thread sufficiently-perhaps it would be better to start a new one if people wanted to continue this discussion.
ENVE contract engineer | Former Zipp test engineer

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CharlesM
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by CharlesM

airwise wrote:Have any of you guys actually won a race on an aero bike?

Just wondering as I've never seen one cross the line first in an amateur road race and I get to see a lot of those.

Given that the rolling resistance of a tyre can vary more than the power gains of these framesets I do honestly wonder why these garner so much attention here when they are both non weight weenie and less enjoyable to ride.



Ignoring one condition / advantage because another exists is, well, ignorant....

airwise
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by airwise

PezTech wrote:
airwise wrote:

Ignoring one condition / advantage because another exists is, well, ignorant....


In which case 99.99% of cyclists are ignorant Pez.

It's also fairly daft to attach huge importance to unproven advantages that may well only exist using crash test dummies in the wind tunnel.

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CharlesM
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by CharlesM

Yeah those silly wind tunnel tests are worthless. It's way better to assume that road surfaces the world over are a match for the drums that Rolling Res tests are done on and just disregard aerodynamics.

F1 & MotGP engineers, Aircraft manufacurers, if they would just pay attention to forums... :wink:


I'm not really saying RR tests are worthless, I'm just saying that just because RR test show one thing doesnt mean people should just ignore aero data...

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djconnel
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by djconnel

Pez: For "everyday riding" aerodynamics is hardly important. Comfort, reliability, and feel are more important. So you optimize each factor based on when that factor is important. You optimize weight for going uphill, you optimize aerodynamics for riding fast, comfort for rough roads, etc.

sawyer
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by sawyer

airwise wrote:Have any of you guys actually won a race on an aero bike?

Just wondering as I've never seen one cross the line first in an amateur road race and I get to see a lot of those.

Given that the rolling resistance of a tyre can vary more than the power gains of these framesets I do honestly wonder why these garner so much attention here when they are both non weight weenie and less enjoyable to ride.


Very few amateurs race on aero road frames. I've seen races being won by aero Cervelos but that's about it. Why? Because it's the only aero road frame to have been around a while and sold in considerable numbers is my guess.

You'll see a huge growth in aero frames over the next few years. You'll see them get lighter, stiffer and more enjoyable to ride. You may even seen one of your races won on one :D
----------------------------------------
Stiff, Light, Aero - Pick Three!! :thumbup:

airwise
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by airwise

PezTech wrote:
I'm not really saying RR tests are worthless, I'm just saying that just because RR test show one thing doesnt mean people should just ignore aero data...


And I'm not saying ignore aero date - just put it in proper perspective. The reason we will see more is that manufacturers are selling the whole idea along with unrepeatable data and huge marketing spend - not because there is any real benefit to real cyclists.

bikedoc
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by bikedoc

no body has won a race because they were on an 'aero' frame or had 'aero' wheels

and i would love to see anyone provide data proving otherwise

sawyer
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by sawyer

airwise wrote:
PezTech wrote:
I'm not really saying RR tests are worthless, I'm just saying that just because RR test show one thing doesnt mean people should just ignore aero data...


And I'm not saying ignore aero date - just put it in proper perspective. The reason we will see more is that manufacturers are selling the whole idea along with unrepeatable data and huge marketing spend - not because there is any real benefit to real cyclists.


A very small benefit yes, but then 100g off a frame is a pretty small benefit on an 85kg rider plus bike weight!
----------------------------------------
Stiff, Light, Aero - Pick Three!! :thumbup:

llhh
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by llhh

bikedoc wrote:no body has won a race because they were on an 'aero' frame or had 'aero' wheels

and i would love to see anyone provide data proving otherwise


When talking aero advantages, would anyone think that Cav taped over his helmet at the Worlds just for the fun of it? ;)

As for data, success in cycling is a combination different factors. How do they weigh in in a racing situation is very difficult to measure. But that does not automatically mean that these individual factors do not exist or should be overlooked, especially in a sport where millimeters and milliseconds matter.

Rhetorical question: how would you measure the importance of pshychological boost in confidence by riding an aero frame as a believer of aero advantage, for example?
Parlee Z1 Super Record / ENVE / Campangolo Bora

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CharlesM
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by CharlesM

People have won races because they were on aero frames and wheels and I would love to see anyone provide data proving otherwise.

:lol:

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Discoverspeed
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by Discoverspeed

This photo has been posted before and it looks to me that an aero frame, a pair of aero wheels with a super rider edged this win... maybe gloveless helped in aerodynamics too? :wink:

Image
Current Bikes: Storck F.3 5.5kg
Colnago Concept Art Deco CHDK 7/6.5kg
Collection: Team Ti Raleigh 753 Vintage Campy
Storck Organic Light 11.1kg
Ex: Storck F0.6 Di2 6kg, Storck F0.7IS Di2 4.8kg, Storck Aero2 7.04kg

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